feat(argo): add update command

docs/argocd/argocd.md

@@ -50,11 +50,20 @@ spec:
 EOF
 ```
 
+## Update ArgoCD
+
+```yaml
+kubectl apply -n argocd \
+    --server-side \
+    --force-conflicts \
+    -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml
+```
+
 ## ArgoCD Applications
 
 This is an example of an ArgoCD Application manifest which deploys this MkDocs application.
 
-```yam
+```yaml
 ---
 apiVersion: "argoproj.io/v1alpha1"
 kind: "Application"